1. Field of the Invention
This invention relates to a semiconductor device, an SRAM and a manufacturing method of a semiconductor device. In particular, this invention relates to a semiconductor device which has an active region and a contact portion connected to the active region, an SRAM and a manufacturing method of a semiconductor device.
2. Description of the Background Art
Technologies for forming a transistor on an SOI substrate have existed conventionally (see “Bulk-Layout-Compatible 0.18 μm SOI-CMOS Technology Using Body-Fixed Partial Trench Isolation (PTI),” 1999 IEEE International SOI Conference, October 1999, pp. 131-132, by Y Hirano et. al.).
An active region that forms a transistor is surrounded by a partial separation insulating film according to the invention of the aforementioned literature. Here, a contact portion is connected to the active region.
In the step of connecting the contact portion to the active region, however, the contact portion is formed in a position that is shifted from the original active region due to shifting during overlapping.
In accordance with the miniaturization of semiconductor devices, the width of active regions tends to be scaled down. When the width of an active region is scaled down, however, the possibility of a contact portion being formed outside of the active region due to shifting during overlapping, as described above, becomes high.
In the case where a contact portion is formed outside of the active region, a portion of the contact portion is connected to the body portion within the SOI layer. As a result of this, a leak current is caused between the contact portion and the body portion.
It is necessary to provide a contact portion on a narrow active region with high precision, in order to prevent the occurrence of such a leak current. This has become a factor in making the manufacture of semiconductor devices difficult.